These handsets will, says Google, get the final version of Android Pie "by the end of this fall". Not very specific and not that helpful considering these handsets were just as valid as test beds as Google's own Pixel devices.

Install Android Pie with a system image

The more traditional way to get the Android Pie is to go the system image/manual flashing route. You can download images from Google and then flash them onto your device, but it will be a fresh install, with everything erased. Here's the site where you can download them.

Pixel 2

Pixel 2 XL

Pixel

Pixel XL

This page details how to flash while also providing step-by-step instructions that'll get you going.

BE WARNED: flashing a system image will wipe all the information off your device, so ensure you back up important data beforehand.